Hot stamping die structure for hot stamp decorating

ABSTRACT

A hot stamping die for decorating the irregular surface of an article utilizing a laminated die comprised of a pair of spacedapart plates having a layer of resilient material sandwiched therebetween. the die is heated and the outermost plate is deformed to match the irregular contour of the surface to be decorated in the stamping operation.

United States Patent 1,164,742 12/1915 Moore .1 101/31 3,296,958 l/l967 Liepelt 101/31 1,071,527 8/1913 Pannier 101/376 1,071,626 8/1913 Pannier [01/376 1,519,481 12/1924 Bing [01/376 2,028,712 1/1936 Swan et a1, 101/379 2,163,948 6/1939 Huebner 101/379 2,351,660 6/1944 Campbell. 101/27 2,722,038 11/1955 Freund 101/31 X 2,738,618 3/1956 Hilder 101/379 2,781,278 2/1957 Harmon 101/426 X 2,858,633 11/1958 Kane 1. 101/27 Primary Examiner--William B. Penn Attorney-Learman, Learman & McCulloch ABSTRACT: A hot stamping die for decorating the irregular surface of an article utilizing a laminated die comprised of a pair of spaced-apart plates having a layer of resilient material sandwiched therebetween. the die is heated and the outermost plate is deformed to match the irregular contour of the surface to be decorated in the stamping operation.

PATENTEDUCT 12 ISTI INVENTOR CARL F GLADEN 45 mm M 7 l I uor STAMPING DIE'S'IRUC'IURE m uo'r STAMP DECORATING This application is a continuation-in-part of U.S. application Ser. No. 603,778 filed in the U.S. Pat. Office on Dec. 22, I966, now abandoned. i

The present relates to the art of hot stamp decorating the irregular surface of an article by utilizing a silicone rubber cushion between two sheets of metal and hot stamp decorating the article with a sheet surface deformed to the irregular surface.

Briefly, according to the present-invention, there is provided a hot stamping die for decorating the irregular surface of an article including a pair of spaced apart plates having a layer of resilient material sandwiched therebetween. Heat is applied to the die to apply the decorative material to the article and one of the plates is utilized to stamp the part. The stamping plate is deformed temporarily so that its stamping surface matches the irregular-surface of the article being decorated.

With the above in view, other advantages of the invention will be pointed out specifically or will become apparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings, in which:

FIG. 1 is an enlarged, side elevational view, in section of an embodiment of the die, mounted on a platen and in engagement with a part;

FIG. 2 isa perspective view of a preferred embodiment of the die formed according to the invention; 7

FIG. 3 is a perspective view illustrating yet another embodiment of the die formed according to the invention, and

v FIG. 4 is a perspective'view illustrating a further modification of the die formed according to the invention.

Referring now to the drawing, a die formed according to the present invention is shown generally at D and includes a pair of spaced apartplates l and l2.having a layerof resilient material'l4 whichdoes not deteriorate when heated at ,hot stamping temperatures, preferably silicone rubber in .the

50-80 durometer range, sandwiched therebetween. The

stamping surface 13 of plate 12 is shown in engagementwith the irregular surface 16 of an article A. Therubber-metal-die forms, in general shapeand appearance a rubber sandwich, and it will be so referred to as thespecification progresses.

This rubber sandwich can be made using an adequate thickness of rubber between a pair of metal plates of predetermined thickness,andthisthickness is determined by the. particularpartbeing stamped. A thick rubberlayer provides more flexibility, and the less uniform the part being stamped,

the thickertherubber layer should be. However, the thicker rubber layer requires a higher temperature for stampinginasmuch as the rubber has certain heat insulating characteristics which are disadvantageous. I

In practice, the metal layer 12 can be very thin shim steel. To obtaingood results when stamping surfaces having raised designs thereon, a verythin shimsteel, 0.005 to 0.0l0:. inch thick may be used. This metal is thin enough to readily flex to fit the irregular surface 16 of part A.

In this sandwich construction, the 0.005 to 0.010 inch thick while steel layer 12 can be 0.010 to 0.0l5 inch thick on the oppositeside. The layer 10 should be conveniently cemented to a platen P using a suitable commercially available die bonding film adhesive and the platen P can be heated to a suitable temperature in any conventional manner, such as by electrical heating elements 30 carried by the platen in the manner as is more particularly disclosed in US. Pat. No. 2,722,038, issued Nov. 1, 1955. In this case, the stamping side 12 can be etched or sand blasted sufficiently to leave approximately 0.005-0.010 inch at the thinnest areas to permit flexing, and most interesting etched designs can be obtained. 1

Referring now to Flg. the die D includes the metal layers 10a and 12a in the sandwich which can .be both formed of copper. with a rubber core 14a therebetween, and experience indicates that 0.040 inch thick copper is ideal for both plates.

steel layer 10 can be If desired, plate 10a may also be formed of aluminum whereas plate 12a may be formed of zinc or other suitable material. A suitable design 20 can be etched or sandblasted on plate 120. The stamping face 13a layer 12a can be etched via the photo engraving process, leaving 0.005-0.010 inch backing as shown at 18 while the raised design portion 20 remains 0.032 inch thick. This particular die has proven particularly successful in the hot stamping of treated automotive instrument panels and should prove invaluable in hot stamping any treated metal surface.

The sandwich process using copper engraved plates is ideal for the printing of display cartons since a certain amount of makeready can be eliminated, thus saving considerable time and labor, and it is recommended that the copper rubber sandwich be used for applications involving temperatures not to exceed 350 F. because bonds are inherently poorer between copper and rubber than steel or aluminum and rubber.

Referring now to the embodiment in FIG. 3, the sandwich die D" is similarly formed with metal layers 10b and 12b hav' ing a layer of silicone rubber 14b sandwiched therebetween. A layer of chrome 22 is placed over the outer surface 13b of plate 12b to provide a hard face having good wearing qualities and adding corrosion resistance. Both steel and copper dies can be chrome plated to a degree which does not deleteriously affect their flexibility.

Referring now to FIG. 4, a die D is a-modification of the embodiment shown in FIG. 1 and is particularly well suited for imprinting designs in the part. Plates 10c and 120, and rubber layer 14c corresponds to plates 10 and I2 and rubber layer 14, respectively. Secured to the outer surface 13c of the plate 12c with a suitable die bonding film is an engraved plate 25 which may suitably be made from copper. When a design or lettering is to be imprinted in the part, it is recommended that plate 25 be formed of 0.032 inch thick copper, etched out to a desirable 0.005 to 0.010 inch thickness as shown at 26, leaving 0.005-0.010 shell. In this instance, plate [2c is formed of 0.005-0.0I0 inch thick steel. The steel layer 12c bonds better .to the rubber than does copper while copper plate 25 provides increased flexibility in the etching of designs therein. The die D' is particularly adapted to the hot stamping of irregular metal surfaces and other high temperature applications up to 450 F..The particular temperature to which the die is heated will depend upon the particular material being stamped. Thus, it may be seen that the die shown in FIG. I may be quickly and easily converted to a die for stamping designs on a part by attaching plate 25 to the outer surface 13c of plate 120.

Where a shallow concave or convex shape is to be decorated, successful dies for this purpose can be made using dead soft, or one-half hard, l/32-inch thick aluminum with a rubber core of l/32l/l6 inch thickness, and etching out the design on the copper side for the stamping. The die then can be easily formed to the shape required. Aluminum to rubber bonds are good up to-500 F., but should not be operated at this temperature for long periods of time as both rubber and bond will break down. Practical operating temperature for this embodiment range between 350 F. and 450- F.

' In the operation of the preferred embodiment illustrated in FIG. 2, it will be assumed that part A is formed of hardened plastic material. The backup plate 10 is secured to the heated platen P by suitable screws or-die bonding film. Heat is thus transferred from the platen P, through plate 10a, to the silicone rubber layer 14, and then to the plate 12.

The irregular surface 16 of part A is then stamped with the surface 13a and the plate 12a is deformed to match the contour of the irregular surface 16. The surface of the part plasticizes under the combined heat and pressure of the die D. The design 20 etched on plate 12a is then impressed into the irregular surface 16. The embodiment illustrated in FIG. 4 operates similarly to the embodiment illustrated in Flg. 3.

In the operation of the embodiment illustrated in FIG. I, the die D is utilized to apply a coating (not shown) to the surface 16 of article A. Before the surface 16 is stamped with the surface 13 of plate 12, a strip of foil 31 is placed therebetween.

The foil may suitably comprise a film of Mylar or cellophane carrier having a coating or pigment vacuum deposited on one side thereof. A release agent is applied between the cellophane and pigment to enable release of the coating when suitable temperature and pressure is applied by die D. A suitable sizing agent may be placed on the outer surface of the pigment to facilitate the bonding of the pigment to the surface 16 of article A. The foil may also comprise what is commonly referred to in the art as roll leaf and may suitably be a layer of precious metal, such as gold. In this embodiment, when the surface 16 is stamped with the surface 13, the coating is transferred from the cellophane carrier to the surface 13. The plate 12 is deformed temporarily to match the contour of the surface l6 to enable a uniform and continuous coating to be applied.

The rubber sandwich process is one that is ideal for use as die cost is considerably less, the appearance of the stamped part is improved, and quantity is enhanced.

From the foregoing description it will be obvious that l have perfected a very simple, practical, and inexpensive hot stamping process and die for hot stamping plastic and painted metal parts of all kinds.

I claim:

1. A hot stamping die construction for decorating under heat and pressure an irregular surface of a plastic part to be decorated, said construction comprising a relatively thin, flexible first metal plate having substantial shear strength and having a stamping surface adapted to bear against said irregular surface of said part, said plate being of such flexibility as to enable it to be deformed temporarily to conform to the irregular surface of said part; a second metal plate spaced from said first metal plate; a layer of resilient, heat-conductive, synthetic rubbery material of substantial thickness relative to that of the first metal plate and sandwiched between and secured to said first and second plates; means for mounting said second plate on a platen adapted to be moved toward and away from said part and operable to press said first plate against said part under sufficient pressure to conform said first plate to said surface of said part; and means for applying sufficient heat to said first plate through said second plate and said rubbery material while said first plate bears against and conforms to the surface of said part to enable heating and decorating of said surface of said part by deforming same.

2. The construction set forth in claim 1 wherein said first plate is steel.

3. The construction set forth in claim 1 wherein said first plate is copper.

4. The construction set forth in claim 1 wherein said first plate is aluminum.

5. The construction set forth in claim 1 wherein said stamping surface of said first plate has a coating thereon of metal harder than the metal of which said first plate is formed.

6. The construction set forth in claim 1 wherein said first plate has secured to its stamping surface a copper plate.

7. The construction set forth in claim 1 wherein said first plate is heated to a temperature not exceeding 500 F.

8. The construction set forth in claim 1 wherein said resilient material is silicone rubber.

9. A hot stamping die construction for decorating under heat and pressure an irregular surface of a part to be decorated, said construction comprising a relatively thin, flexible first metal plate having substantial shear strength and having a stamping surface adapted to bear against said irregular surface of said part, said plate being of such flexibility as to enable it to be deformed temporarily to conform to the irregular surface of said part; a second metal plate spaced from said first metal plate; a layer of resilient, heat-conductive, synthetic rubbery material of substantial thickness relative to that of the first metal plate and sandwiched between and secured to said first and second plates; a thin layer of film having a release coating thereon interposed between said first plate and said part to be decorated; means for mounting said second plate on a platen adapted to be moved toward and away from said part and operable to press said first plate against said part under sufficient pressure to conform said first plate to said surface of said part; and means for applying sufficient heat to said first plate through said second plate and said rubbery material while said first plate bears against and conforms to the surface of said part to enable the release coating on said film to be transferred to said part. 

1. A hot stamping die construction for decorating under heat and pressure an irregular surface of a plastic part to be decorated, said construction comprising a relatively thin, flexible first metal plate having substantial shear strength and having a stamping surface adapted to bear against said irregular surface of said part, said plate being of such flexibility as to enable it to be deformed temporarily to conform to the irregular surface of said part; a second metal plate spaced from said first metal plate; a layer of resilient, heat-conductive, synthetic rubbery material of substantial thickness relative to that of the first metal Plate and sandwiched between and secured to said first and second plates; means for mounting said second plate on a platen adapted to be moved toward and away from said part and operable to press said first plate against said part under sufficient pressure to conform said first plate to said surface of said part; and means for applying sufficient heat to said first plate through said second plate and said rubbery material while said first plate bears against and conforms to the surface of said part to enable heating and decorating of said surface of said part by deforming same.
 2. The construction set forth in claim 1 wherein said first plate is steel.
 3. The construction set forth in claim 1 wherein said first plate is copper.
 4. The construction set forth in claim 1 wherein said first plate is aluminum.
 5. The construction set forth in claim 1 wherein said stamping surface of said first plate has a coating thereon of metal harder than the metal of which said first plate is formed.
 6. The construction set forth in claim 1 wherein said first plate has secured to its stamping surface a copper plate.
 7. The construction set forth in claim 1 wherein said first plate is heated to a temperature not exceeding 500* F.
 8. The construction set forth in claim 1 wherein said resilient material is silicone rubber.
 9. A hot stamping die construction for decorating under heat and pressure an irregular surface of a part to be decorated, said construction comprising a relatively thin, flexible first metal plate having substantial shear strength and having a stamping surface adapted to bear against said irregular surface of said part, said plate being of such flexibility as to enable it to be deformed temporarily to conform to the irregular surface of said part; a second metal plate spaced from said first metal plate; a layer of resilient, heat-conductive, synthetic rubbery material of substantial thickness relative to that of the first metal plate and sandwiched between and secured to said first and second plates; a thin layer of film having a release coating thereon interposed between said first plate and said part to be decorated; means for mounting said second plate on a platen adapted to be moved toward and away from said part and operable to press said first plate against said part under sufficient pressure to conform said first plate to said surface of said part; and means for applying sufficient heat to said first plate through said second plate and said rubbery material while said first plate bears against and conforms to the surface of said part to enable the release coating on said film to be transferred to said part. 